Air pollution is getting significantly worse in recent years, and the incidence of lung disease is greatly increasing as well. Pulmonary function of a large portion of people has seriously decreased accordingly, and this symptom is not easily to be aware of subjectively. Early stage lung diseases are not easily diagnosed by the patient, and consequently patient's miss the opportunity for early treatment of the disease. A doctor may also neglect potential symptoms if the patient does not inform the doctor. Even if pulmonary radiography is taken, the disease is often discovered after relevant conditions deteriorate. A conventional pulmonary function test is to use a pulmonary function measuring device for testing. A pulmonary function measuring device must be located in a confined space with constant temperature and pressure, and then people must take further steps for pulmonary function tests under the doctor's instruction. However, conventional pulmonary function measuring devices are bulky, the operation is complicated and the test is expensive. Therefore, conventional devices may be neither a household medical equipment, nor portable. These devices are also not operable under exercising conditions. Conventional methods to measure resistances are usually impulse oscillometry and plethysmogrophy, however, the equipment implementing these methods are not only expensive and more complicated while in use, but are also effective only to the patients with moderate conditions; measurement utilizing these methods for patients with mild or severe conditions are less effective. Because these kinds of pulmonary function measuring devices are less convenient, people often miss the opportune time of treatments on early pulmonary lesions due to lack of motivation of regular inspection of pulmonary function. As a result, a cheaper and portable pulmonary function measuring device, which is also capable of wirelessly transmitting the measurement results to the analysis systems in the hospital for informing the users their pulmonary function status, is strongly demanded.